source: mainline/uspace/srv/fs/exfat/exfat_directory.c@ d963742

/*
 * Copyright (c) 2011 Oleg Romanenko
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup fs
 * @{
 */ 

/**
 * @file        exfat_directory.c
 * @brief       Functions that work with FAT directory.
 */

#include "exfat_directory.h"
#include "exfat_fat.h"
#include <libblock.h>
#include <errno.h>
#include <byteorder.h>
#include <mem.h>
#include <str.h>


void exfat_directory_init(exfat_directory_t *di)
{
        di->b = NULL;
        di->nodep = NULL;
        di->bs = NULL;
        di->blocks = 0;
        di->pos = 0;
        di->bnum = 0;
        di->last = false;
}

int exfat_directory_open(exfat_node_t *nodep, exfat_directory_t *di)
{
        exfat_directory_init(di);
        di->nodep = nodep;      
        if (di->nodep->type != EXFAT_DIRECTORY)
                return EINVAL;

        di->bs = block_bb_get(di->nodep->idx->devmap_handle);
        di->blocks = di->nodep->size / BPS(di->bs);
        return EOK;
}

int exfat_directory_close(exfat_directory_t *di)
{
        int rc=EOK;
        
        if (di->b)
                rc = block_put(di->b);
        
        return rc;
}

static int exfat_directory_block_load(exfat_directory_t *di)
{
        uint32_t i;
        int rc;

        i = (di->pos * sizeof(exfat_dentry_t)) / BPS(di->bs);
        if (i < di->blocks) {
                if (di->b && di->bnum != i) {
                        block_put(di->b);
                        di->b = NULL;
                }
                if (!di->b) {
                        rc = exfat_block_get(&di->b, di->bs, di->nodep, i, BLOCK_FLAGS_NONE);
                        if (rc != EOK) {
                                di->b = NULL;
                                return rc;
                        }
                        di->bnum = i;
                }
                return EOK;
        }
        return ENOENT;
}

int exfat_directory_next(exfat_directory_t *di)
{
        int rc;

        di->pos += 1;
        rc = exfat_directory_block_load(di);
        if (rc!=EOK)
                di->pos -= 1;
        
        return rc;
}

int exfat_directory_prev(exfat_directory_t *di)
{
        int rc=EOK;
        
        if (di->pos > 0) {
                di->pos -= 1;
                rc=exfat_directory_block_load(di);
        }
        else
                return ENOENT;
        
        if (rc!=EOK)
                di->pos += 1;
        
        return rc;
}

int exfat_directory_seek(exfat_directory_t *di, aoff64_t pos)
{
        aoff64_t _pos = di->pos;
        int rc;

        di->pos = pos;
        rc = exfat_directory_block_load(di);
        if (rc!=EOK)
                di->pos = _pos;
        
        return rc;
}

int exfat_directory_get(exfat_directory_t *di, exfat_dentry_t **d)
{
        int rc;
        
        rc = exfat_directory_block_load(di);
        if (rc == EOK) {
                aoff64_t o = di->pos % (BPS(di->bs) / sizeof(exfat_dentry_t));
                *d = ((exfat_dentry_t *)di->b->data) + o;
        }
        
        return rc;
}


/**
 * @}
 */